Read: George W Bush's inauguration day letter to Barack Obama

As Donald Trump prepares to take over as the 45th President of the United States (US), two inauguration letters from past presidents to their successor have been made public by the National Archives and Records Administration for the first time.

Barack Obama will be handing over the baton to Trump on Friday and will be penning his own letter to the US president-elect before he leaves office.

ABC News obtained the letters written by former presidents Bill Clinton and George W Bush from the National Archives and Records Administration.

JUST IN: Bill Clinton's letter to George W. Bush & George W. Bush's letter to Barack Obama made public for 1st time https://t.co/bZ4hZnbouv pic.twitter.com/4uHV5pByRs

— ABC News Politics (@ABCPolitics) January 19, 2017

In his message to Obama, George W Bush wrote: "There will be trying moments. The critics will rage. Your “friends” will disappoint you. But, you will have an Almighty God to comfort you, a family who loves you, and a country that is pulling for you, including me."

Clinton wrote to Bush, "You lead a proud, decent, good people. And from this day you are President of all of us. I salute you and wish you success and much happiness."

Trump's inauguration will be held on January 20 in Washington DC.